Footpads, hooves, horns and antlers

Question 1

How are the footpads in carnivores named?

Answer 1

Pads named after underlying region. (ie carpal pad, digital pads, metacarpal/metatarsal pads)

Question 2

What is the main function of footpads?

Answer 2

They act as shock absorbers protecting underlying joints

Question 3

The digital footpads are homologous with…

Answer 3

The bulb in ruminants and pigs
The frog in horses

Question 4

Describe the structure of the footpads

Answer 4

Thick subcutis with adipose tissue, partitioned by collagen and elastic fibres.
Footpads are hairless and thickly keratinised epidermis.
Footpads have eccrine sweat glands to increase grip

Question 5

Describe cat claws at rest

Answer 5

cat claws are retracted into pockets of skin by elastic ligaments that run from 2nd and 3rd phalanges. When cat unsheathes claws the action of the digital flexor muscle overcomes tension in elastic ligaments.

Question 6

Describe the epidermal - dermal junction in nails, claws and hooves

Answer 6

the nail, claw and hoof are epidermal structures anchored to underlying dermis by interdigitations of laminae. There is NO subcutis so the dermis (also known as the quick) of the claw, hoof and nail is closely adhered to periosteum of distal phalanx.

Question 7

Describe why you need to be careful when clipping claws?

Answer 7

The quick of the claw contains nerves and blood vessels. You must be careful to avoid the quick since it can be painful and bleed

Question 8

Which digit is weightbearing in horses?

Answer 8

Digit III is weightbearing (‘so NO foot, NO horse’)

Question 9

What are the functions of nails, claws and hooves?

Answer 9

-Protects the distal digit
-Tools for scratching, digging etc
-Defence/hunting
-Blood circulation (in horses)

Question 10

What happens if there is disturbed growth of nails, claws and hooves?

Answer 10

Transverse ridges

Question 11

How are the digits numbered?

Answer 11

Medial to lateral I-V

Question 12

What is another name for the dermis of the hoof?

Answer 12

Corium

Question 13

What are the names of the 3 layers of the hoof epidermis

Answer 13

Stratum externum
Stratum medium
Stratum internum

Question 14

True or False
There are many nerves and blood vessels in the hoof epidermis

Answer 14

False
There are NO blood vessels or nerves in the hoof epidermis - all comes via diffusion from the dermis.

Question 15

What is the white line made up from?

Answer 15

The worn end of the epidermal laminae + The interlamellar horn from terminal papillae

Question 16

Describe the venous return in horses?

Answer 16

Compression of the frog pushes digital cushion outwards and squashes the hoof cartilage. Venous plexuses in the cartilages are squashed squeezing blood out into digital veins. With each step compression of cartilage aids venous return.

Question 17

what is the name of the attachment on the skull that antlers grow from?

Answer 17

Pedicle

Question 18

what are antlers covered in when growing?

Answer 18

well-vascularised skin (‘‘in velvet’’)
Mature antler is exposed bone

Question 19

How often are antlers grown/shed?

Answer 19

Antlers are shed/regrown every year (cycle related to sex hormones)

Question 20

True or False
Horns are NEVER shed

Answer 20

True
Horns are NOT branched and NEVER shed. They are grown with age

Question 21

How are horns grown?

Answer 21

Horn bud starts out in the subcutis and later fuses to the skull

Question 22

What are some of the similarities & Differences between horses and antlers?

Answer 22

Similarities
-Initially covered in epidermis
-Both contain bone
-Located on frontal bone
-bigger/present more in males
-get bigger with age

Differences
-Horns develop in subcutis
-Horns covered in keratin sheath
-Horns never shed
-Horns have no branches